Not having heard this term before, I Googled it. There are similar, differently-named, products in my country, but terms and conditions will vary between institutions, never mind between countries.

Without going deeply into the matter it seems that in Canada there are available both redeemable and non-redeemable certificates, the principal difference being betrayed by their respective titles. You would need to consult the T&Cs of your particular investment institution for guidance if there may be some 'get-out' allowing an early exit in your particular case, but the general idea is that the money is locked away for an agreed time in exchange for an agreed rate of return, so I would not be hopeful.

This National Bank link seems to give a fairly typical example of what is available.

I did wonder whether there might be some sort of secondary market where a GIC might be saleable at a discount to a third party (as is the case for life policies here) but I saw no evidence of such a market.